There are a number of systems which require the transportation of small articles that are suitable for automation. For example, the transportation of samples and sample holders in automated clinical analyzers requires repetitive movement of samples through various stations including for example, reagent dispensing, mixing, incubation, monitoring, and disposal stations. In such systems, the sample holders can comprise test tubes, cuvettes, test slides, etc., which require transportation. In order to automate the transportation of such sample holders, highly accurate, light weight grippers are required.
To date, pneumatic grippers have been proposed for use in clinical analyzers and similar systems. However, the use of pneumatic grippers in such systems involves a number of disadvantages. For instance, the use of pneumatic grippers requires a controlled source of pressurized fluid which might add to the cost and complexity of the overall system. The pneumatic system for pneumatic grippers may also leak over time. If pneumatic system leaks develop in the vicinity of the gripper jaws, there is the possibility of dispersing hazardous material from a sample holder. A pneumatic system, however, can be used in the present invention for non-hazardous applications.
Small parts grippers are also applicable for use in semiconductor, hard drive, and other small part processing operations. Some of these processes involve environments which are hostile to various materials and moving parts, and therefore pose particular problems for parts grippers. For example, polishing processes for semiconductors and hard drives often utilize deionized water and polishing compound slurries, thus providing an environment which is particularly hostile to metal bodied parts grippers.